When I was working on my play "Empty Bowl" I built some extension for MediaWiki. This lets you write scripts quite easily. You get easy revisioning and diffs. The scripts look something like this:
<c>Seth</c> The girl is not the problem. This house- I won't marry. <sd>Laurel enters</sd> <c>Laurel</c> Sure you will Seth.
And when you view or print them they look like this:
|<sd>||<sd>Stage Direction on its own line</sd>|
|<isd>||<isd>Inline Stage Direction within a line</isd>|
I have no plans to keep developing this, but I'm open to writing a couple more plugins if anyone wants them. I'm open to farming it out to some source control system if anyone else would like to keep developing.
Download Mediawiki Playwrighting Extension